Although it has been demonstrated that patient histories can be obtained effectively by the use of computer-based systems, the broad evaluation of the importance and usefulness of such histories in a variety of medical settings has been inhibited by the high cost of implementation of such systems and the performance compromises that have been made in order to reduce costs. Development of a novel method of organizing such a system that promises to reduce such costs substantially without compromising performance is the central point of this proposal. The approach uses distributed computing, with the mass storage needed to support the individual patient-interactive processors centralized. The key feature of the new approach is the use of one-way communication from the central mass store to the distributed processors via a tree-like distribution system identical to a cable-television distribution network. Information is continuously and repetitively broadcast from the central source to all terminals of the network; each of the distributed processors extracts from the broadcast stream that information which is needed. The absence of any need for processors to send requests to the central storage device eliminates interference between processors, and permits the addition of an arbitrarily large number of terminals to the network. Reduction of terminal cost is an important consideration in such a scheme. The appropriate form of a low-cost terminal to facilitate patient interaction will be determined. We propose to design and implement such a system in a form that is compatible with a widely-used system for generating and administering patient history questionnaires. The system will be used and evaluated in the Washington University Department of Psychiatry as a research tool for the development of psychiatric diagnosis criteria, and made available for other experimental uses.